Least Tern

Sternula antillarum

Our smallest tern. Often seen flying low over the water, with quick deep wingbeats and shrill cries. Usually hovers before plunging into water for tiny prey; does more hovering than most terns. Populations are endangered in many areas because of human impacts on nesting areas, especially competition for use of beaches. However, Least Terns in some parts of the east are now nesting successfully on gravel roofs near the coast.

Conservation status

Several populations are endangered. On coasts, nesting areas often disturbed by beach-goers. On inland rivers, fluctuating water levels (from releases from major dams) often flood out nesting sites on sandbars.

Sea beaches, bays, large rivers, salt flats. Along coast generally where sand beaches close to extensive shallow waters for feeding. Inland, found along rivers with broad exposed sandbars, lakes with salt flats nearby. In winter found along tropical coasts, sometimes well out to sea.

Our smallest tern. Often seen flying low over the water, with quick deep wingbeats and shrill cries. Usually hovers before plunging into water for tiny prey; does more hovering than most terns. Populations are endangered in many areas because of human impacts on nesting areas, especially competition for use of beaches. However, Least Terns in some parts of the east are now nesting successfully on gravel roofs near the coast.

Photo Gallery

Feeding Behavior

Forages by flying over water, hovering, and plunging to catch prey just below water's surface. Sometimes dips down to take prey from surface of water or land, and may catch insects in flight.

Eggs

1-3, perhaps rarely more. Buff to pale green, blotched with black, brown, gray. Incubation is by both sexes; female may do more in early stages, male more later. In very hot weather, adult may dip into water and wet belly feathers to cool eggs. Incubation period 20-25 days. Young: Leave nest a few days after hatching, find places to hide nearby. Both parents feed young. Age at first flight about 19-20 days; young may remain with parents another 2-3 months. One brood per year, sometimes two in south.

Young

Leave nest a few days after hatching, find places to hide nearby. Both parents feed young. Age at first flight about 19-20 days; young may remain with parents another 2-3 months. One brood per year, sometimes two in south.

Diet

Fish, crustaceans, insects. Diet varies with season and location; mostly small fish, crustaceans, and insects, also some small mollusks and marine worms.

Nesting

Nests in colonies, sometimes in isolated pairs. In courtship, male (carrying fish in bill) flies upward, followed by female, then both glide down. On ground, displays include courtship feeding. Nest site is on open ground (or on gravel roof). Nest is shallow scrape, sometimes lined with pebbles, grass, debris.

How climate change could affect this bird's range

In the broadest and most detailed study of its kind, Audubon scientists have used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change.

Least Tern

Each map is a visual guide to where a particular bird species may find the climate conditions it needs to survive in the future. We call this the bird’s “climatic range.”

The colors indicate the season in which the bird may find suitable conditions— blue for winter, yellow for summer (breeding), and green for where they overlap (indicating their presence year-round).

The darker the shaded area, the more likely it is the bird species will find suitable climate conditions to survive there.

The outline of the approximate current range for each season remains fixed in each frame, allowing you to compare how the range will expand, contract, or shift in the future.

The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

You can play or pause the animation with the orange button in the lower left, or select an individual frame to study by clicking on its year.

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.

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